2019HSCShort answer

Q33 (b) (i)

2 marks

Question

Alzheimer’s disease causes destruction of brain tissue, dementia and eventually death. The diagram shows the effect of Alzheimer’s disease on the brain.
The gene with the greatest known effect on the risk of developing late-onset Alzheimer’s disease is called APOE. It is found on chromosome 19.
The APOE gene has multiple alleles, including e2, e3 and e4.
What are multiple alleles?

Try the question before revealing the answer.

Solution

Criteria	Marks
Provides a suitable definition	2
Provides some relevant information	1

Sample answer:

Alleles are different versions of a gene. ‘Multiple alleles’ refers to three or more versions of a gene existing in a population.

Supplied marking guidance · human reviewed

Compare this with your working, not only your final sentence.

Syllabus alignment

Module 5 · Heredity

Genetic VariationInterpret inheritance patterns, pedigrees and Punnett squares to model genotype combinations.

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